The present invention relates generally to computerized information retrieval, and more specifically to multilingual document retrieval.
A global information economy requires an information utility capable of searching across multiple languages simultaneously and seamlessly. However, when a scientist, patent attorney or patent examiner, student, or any information seeker conducts an electronic search for documents, that search is usually limited to texts in the searcher's native tongue, even though highly relevant information may be freely available in a foreign language. Searching for information across multiple languages invariably proves daunting and expensive, or fruitless and inefficient, and is therefore rarely done.
Patent searching is but one example where limitations of language pose significant obstacles. In prior art terms, all languages are created equal. As a practical matter, a patent examiner in a given country tends to have the most meaningful access to documents in that country's language. Since the most pertinent prior art may be in a different language, patent examiners are often prevented from carrying out an effective examination of patent applications.
The conventional approach to multilingual retrieval is to translate all texts into one common language, then perform monolingual indexing and retrieval. Such systems have several disadvantages. First, the machine translation process, although fully-automated, is often time-consuming and expensive. It is also highly inefficient, since all documents must be translated even though only a small fraction of documents will be relevant to any given query.
Second, the process of translation inevitably introduces errors and ambiguities into the translated document, making subsequent indexing and retrieval troublesome. For example, translation systems perform poorly with specialized discourse (medicine, law, etc.), and are often unable to disambiguate polysemous words (those words with multiple meanings) correctly.